- Oceania (UK: /ˌoʊsiˈɑːniə, ˌoʊʃi-, -ˈeɪn-/ OH-s(h)ee-AH-nee-ə, -AY-, US: /ˌoʊʃiˈæniə, -ˈɑːn-/ OH-shee-A(H)N-ee-ə) is a geographical region including Australasia, Melanesia, Micronesia, and Polynesia. Outside of the English-speaking world, Oceania is generally considered a continent, while Australia is regarded as an island or a continental landmass contained inside of the larger continent of Oceania. Spanning the Eastern and Western Hemispheres, at the centre of the water hemisphere, Oceania is estimated to have a land area of about 9,000,000 square kilometres (3,500,000 sq mi) and a population of around 44.4 million as of 2022. When compared to the continents (which it is often compared to, not including Australia), Oceania is the smallest in land area and the second-least populated after Antarctica.